What you’re proposing would have to go through some circus like
- Call to domain/my-page.html
- Discourse 404’s
- Your custom JS catches that 404, recognizes that it came from your custom route somehow, and… renders the whole template into the 404 div?
- Meanwhile, it also loads a react component, which… I guess gets slid into a particular DOM element using react-dom-inject or something?
- Then it subscribes to messageBus, err maybe by loading something like
let messageBus = Discourse.__container__.lookup('messageBus:main').subscribe? (<-- this code I think still works today, but likely won’t forever, or even for much longer)
I don’t quite get it; why is creating a custom plugin, or using Ember, not an option here?
I get that the plugin architecture and perhaps Ember has a steep learning curve, but this is really using a 
to churn the butter.